We propose a series of structural and mechanistic studies on members of the 70 kilodalton (kDa) heat-shock-like protein family. Based on sequence data for several of these proteins, protein family. Based on sequence data for several of these proteins, plus delineation of the function of the bovine clathrin uncoating ATPase (HSC70), we propose a working model: all 70 kDa heat shock proteins evolved from a common ancestor, maintaining a highly conserved ATPase domain and developing specialized substrate recognition domains. They all should have similar tertiary structures, and all probably catalyze macromolecular rearrangements of some type using the same fundamental mechanism. We will initiate our studies on the representative of this protein family for which a biochemical function is well-understood, bovine HSC70. We will solve the x-ray crystallographic structure of its 44 kDa ATPase core, and will attempt to crystallize and solve the structure of the intact HSC70. We are cloning and will sequence cDNA for the HSC70 mRNA; we will attempt to construct a recombinant overproducer of the protein. We will pursue protein modification (mutagenesis) experiments on HSC70 to address mechanistic questions of substrate recognition and conformational change. A second representative on which we will pursue similar studies in tandem is the bovine glucose regulated protein.